How is it that so many people said that the GH3 was too big and that it would never sell, but then, it was in demand so much, and the GH4 is repeating that, even though Panasonic increased production?
Yesterday, I traded my Panasonic GH3 while the value was still good (I got US$500), for an Olympus E-M1. They did not yet get their GH4 shipment from last week, which says either they're not producing them as well as expected or demand has been really good--better than the GH3 demand.
I waited several months to get my GH3 and it was easy by that time. I didn't want to wait for the value to fall for trade-in, so I traded it while the GH4 was still difficult to get. By the time the GH4 is readily available, I'll have learned to use (/love/hate/deal with) the E-M1.
My initial few hours with the E-M1 produced discomfort for me because of the small battery/small grip size. It was especially apparent that it was too uncomfortable to use with Four-Thirds lenses because of the weight imbalance, as the grip was almost cutting into my fingers.
For the moment, I'll miss the fully-articulated rear display. There is no way to use the E-M1 in portrait orientation and look down at the display, for instance. This is something the GH3 and E-5 did so well. However, the EVF is quite a bit more advanced than the GH3's EVF.
It should be interesting to see if the 12-40mm lens seems more capable with the 5-axis image stabilization. I suspect it will be working until I adapt my grip. As well, the Panasonic 35-100mm lens on it may prove to be okay, but the huge lens flare issue won't go away just because it's on a competitor's camera body.
Oh, one thing I've noticed over the pre-production version I used--I can do a half-press without taking a shot. There are some spongy buttons on the back, but thankfully, the shutter release is more solid in production.
In the registration survey, Olympus asked about video, and I had to say that I wouldn't really be using video with the E-M1. They didn't give it much functionality, so I won't be using it. When I have my GH4, then, I can do video again. I'm beginning to think that my iPhone 5c has better capabilities than Olympus has in any of their camera bodies but then, I buy Olympus for still photography.
Update 2014.06.13: The E-M1 is a good camera with an angular grip and tiny battery. I think you know what suggestion I would make to improve the camera, as it is not bad otherwise.
I got a few photos at Asbury Park beach and boardwalk with the E-M1 and 12-40mm f/2.8 lens.
For comparison, I have a few from the beaches near Manasquan, NJ, taken with the GH3 and 12-40mm f/2.8:
Update 2014.06.15: I have really found the E-M1 grip uncomfortable, just with the 12-40mm f/2.8 lens. I don't see how so many find it comfortable. It feels like it's almost cutting into my fingers. I understand that they wanted to make it compact as a hedge against those who would complain about it being too big, plus they could re-use the tiny battery from their other micro Four-Thirds bodies.
I haven't used it enough but I don't see any huge difference in image quality from the GH3's sensor. People complained that there was more noise, but I think it's negligible, at least using Capture One Pro 7.
The rear display out in the open also bothers me. Unlike the E-1, there is no plastic shield to keep it from damage or my nose. Of course, the display is active too often, and I'm sure that there is a setting for that, to save battery life.
It seems odd to hear the 5-axis sensor shift image stabilization. I'm sure that was quite a concern for many people picking up the E-M1 for the first time. I guess I didn't hear it with the pre-production models because so many of us were talking.
After all this, I'm glad to have it, but I'm all the more impatient to get a GH4.
Update 2014.12.16: There was a pre-Black Friday $200 discount on the GH4. This made it a sensible purchase. While I've become accustomed to the E-M1, the GH4 felt immediately comfortable. Even my extra battery from the GH3 still seemed to be nearly fully charged after about 6 months, happy to see the GH4.
Starting to do video, the GH4 is full of features. However, it feels as though it's as good a stills camera body. It took a very long time for it to become available, but it gave me time to become comfortable with the supposed replacement for the E-5 (the E-M1) I have.
Update 2015.09.13: I sent the E-M1 away for repair. Unfortunately, a BMX/Freestyle rider managed to hit it by riding his bike under the canopy where we were all not doing things like that, and broke the eye cup mount. I used it for a while with jagged edges until a few days ago when the shutter came down and wouldn't go back up. I apparently exceeded the 150,000 actuations.
I have two newer alternatives: the Nikon D7200 and the Panasonic GX8. Both are so new that there are no firmware fixes yet. The GX8 is easier to use because of my familiarity with the GH3 and GH4 but it is still a handful. The D7200 defies any clear organization and has been two handfuls, and as a dSLR, it deserves to be two.
The GH4 continues to be interesting. I've put over 100 videos on YouTube, almost all of which were assembled using 1080p clips from the GH4. The GX8 is similarly capable, although its ability to do 4K video is limited.